Electric signaling system



M. L. NELSON ELECTRIC SIGNALING SYSTEM Original Filed D60. 22, 1934 INVENTOR MARTIN L. N ELSON ATTORNEY.

March 30, 1937.

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Patented Mar. 30, 1937 UNITED STATES PATENT OFFICE ELECTRIC SIG NALING SYSTEM Martin L. Nelson, Park Ridge, 11]., assignor to Associated Electric Laboratories, Inc., Chicago,

111., a corporation of Delaware 7 Claims.

This invention relates in general to railway signaling systems but more particularly to highway crossing signaling systems for operating signals at a highway crossing to warn motorists of approaching trains.

The main object of the present invention is the provision of a simple and reliable relay arrangement for controlling the flashing of lamps at a highway crossing to designate the approaching of one or more trains.

A feature of the invention relates to the provision of arrows which when illuminated by approaching trains indicate whether one or more trains are approaching the crossing by indicat ing the direction such trains are travelling, or if desired the direction from which the train is approaching the crossing.

This application is a division of my prior application Serial No. 758,719, filed December 22, 1934.

The above and other objects of the invention will beapparent from the following specification when read in connection with the accompanying drawing.

In the drawing two railroad tracks, track I and track 2 for east-bound and West-bound traflic, are shown. A highway crossing crosses the tracks as indicated near the center of the drawing and such crossing is protected by gates. Crossing signals, such as shown in the lower right-hand corner of the drawing, are also provided'at the crossing to warn -motorists of approaching trains. The crossing signal comprises the lamps LI and L2 adapted to be alternately flashed, arrows AI and A2 also adapted to be illuminated to indicate the direction of travel of the approaching train ortrains and other conventional railroad crossing signs. The arrows AI and A2 may be either neon tube lamps or may be a series of lamps for illuminating the arrows shown.

Along the insideof one of the rails of each track are placed contactors, such as El, E2, WI, and W2, for controlling the circuits of relays ERI ERZ, and WRI and WRZ. These contactors may be substantially of the same design and operation as disclosed in the application of H. F. Obergfell and G. W. Elckenberg, Serial No. 639,558, filed October 26, 1932, wherein the plunger is operated by the train wheels to cause the operation of the circuit controlling contacts in the associated housing. Contaetor EI is placed along east-bound track I on the left-hand side of the crossing at a predetermined distancefrom the crossing, while contactor E2 is placed along track I on the right-hand side a short distance from the crossing. Contactors WI and W2 are similarly placed for west-bound track 2. If desired,'different sections of the'tracks may be insulated and instead of using contactors, track relays may be used. For example, the track relay shown to the right in the drawing may be substituted for contactor E2. The circuits of relays ERI and ERZ are controlled by contactors El and E2 and the circuits of relays W-RI and WR2 are controlled by contactors WI and -W2. Relays D and U are alternating current relays for controlling the operation of the gate motor GM. ContactsDC are contacts controlled by the gate and are normally closed when the gate is up. Contacts UC are contacts controlled by the gate and are normally open when the'gate is up. Contact DC controls the circuit of A. C. relay D and contacts UC controlsthe circuit of A. C. relay U. The contacts DC open when the gates are lowered to a predetermined position and do not again close until the gates are raised to a predetermined position. Contacts UC close when the gates are lowered to a predetermined position and do 'not again open until the gates are raised to a predetermined position. Agate-limit switch GLS is normally open when the=gates are in their normal raised positions and close as soon as the gates are moved therefrom. A bell R, is

associatedwith the crossing to sound an audible alarm to Warn motorists. Relays D and U and the gate motor GM are operated from the 110 volt A. C. source indicated onthe drawing. The various other relays shown are operated from the source B while the bell R is operated from the source B.

Relays I, 2, and 3 are retarded relays which operate in a definite sequence after being initially operated to control the two differential relays 4 and 5 which in turn control the flashing of lamps LI and L2.

All the circuits are shown at normal position with relays ERI, ER2, 'WRI and WR2 energized over their stick circuits. The circuit over which relays ERI and ER2 are energized maybe traced as followsz-from positive pole of source B, contactor springs El, armature -6I, through the lower windings of relays ERI and ER2 in series, and through the upper windings of relays ERI and ERZ in multiple to the negative pole of source B. Relays WRI and WR2 are energized over the'following circuit; from positive pole of source B, contactor springs WI, armature 'II, through the lower windings of relays WRI and WRZ in series, and through the upper windings of relays WLI and WRZ in multiple to the negative pole of source B.

In order to describe the circuit operations, it will be assumed that the wheels of an eastbound train in approaching the crossing operates contactor El thereby opening the stick circuit of relays ER! and ER2 which accordingly deenergize. At armature 6| the previously traced stick circuit is opened to prevent the reenergization of relays ERI and ER2 from contactor El armature 62 completes a circuit for operating the audible bell R, and armature 63 connects positive pole of source B to conductor 8i to complete circuits for relays l, 2, 3, 4, and 5. At armature 64 relay ERZ completes a circuit for A. C. relay D, at armature 65 opens a point in the circuit for A. C. relay U, and at armature 65 completes a circuit for illuminating the arrow Al. The circuit for operating the audible bell R may be traced from the negative pole of battery B, armature 62, and through the bell R to the positive pole of battery B. The energizing circuit for relay I may be traced from positive pole of source B, conductor 61, armature 3|, and through the winding of relay I to negative pole of source B, the circuit for relay 2 extends from conductor 67 by way of armature through the winding of relay 2 to the negative pole of source B and the circuit for relay 3 extends from conductor 61 by Way of armature 2| through the winding of relay 3 to negative pole of source B. Since relays I, 2, and 3 are retarded the same do not immediately energize. At this time a circuit may also be traced for differential relays 4 and 5 as followsz-from positive pole of source B, ar-

mature 63, conductor 67, armature 3| to point 68 where the circuit divides, one branch extending by way of armature 4| and resting contact and through the lower winding of relay 4 to negative pole of source B, the other branch extending from point 68 by way of normally closed springs controlled by armature 5| and through the upper windings of difierential relays 4 and 5 in multiple to negative pole of source B. Relay 4, being differential, and having both its windings energized does not energize at this time, but differential relay 5, since only its upper winding alone is energized at this time, operates armature 5|. Armature 63 also closes a circuit for illuminating lamp L2 as follows:from positive pole of source B, armature S3, conductor El, armature 42 and resting contact, and through the filament of lamp L2 to negative pole of source B. The circuit for illuminating arrow Al may be traced from positive pole of source B, armature 65, and through the lamps (not shown) in Al, or through the neon tube as the case may be to negative pole of source B. The arrow may point in the direction the train is travelling, or, if desired, may point in the direction the train is approaching the crossing.

The circuit for energizing A. C. relay D may be traced from one terminal of the llO-volt A. C. source, conductor 49, armature fi l, springs DC, winding of A. C. relay D by way of conductor to the other terminal of the -volt A. C. source. At armature l6 relay D completes the circuit for the gate motor GM as follows: from the A. C. source, conductor 4|}, armature 76, through the motor GM, and conductor 39 to the A. C. source. The gate motor op rates over this circuit and lowers the gates across the crossing. When the gates reach a predetermined position springs DC open the circuit to relay D and springs UC close to prepare a circuit for relay U.

Relay D at armature 16 opens the gate motor circuit and the gates remain in their lowered position until relay U is later energized.

The gate switch GLS closes when the gates are lowered and completes an obvious circuit for relay 6. Relay 6 at armature 18 closes a shunt around contacts 62 to maintain the circuit to bell R closed and at armature F9 connects positive battery to conductor 6'! in order to maintain the operation of the flashing relay group and the flashing of lamps LI and L2.

As soon as relay ERI deenergizes, said relay at armature 63 completes the previously traced circuits for relays l, 2, 3, t, and 5 but relay 5 is the first to operate since relays i, 2, and 3 are retarded and differential relay 4 has both its windings energized. Relay 5 at armature 5| opens the original circuit through the upper windings of relays 4 and 5 and substitutes a new circuit for these upper windings from conductor 6'! by way of the working contact of armature 5| before the original circuit is opened at the normally closed contacts of this armature.

Any one of the three retarded relays l, 2, or. 3, may operate first but after once started in operation these relays operate in a definite sequence as long as the positive pole of source 13 is connected to conductor 61. This sequence will be apparent from the following description. For this purpose, it will be assumed that relay I is the first to operate and said relay at armature opens the circuit to relay 2 to prevent its operation. The resistances Rl, R2, and R3 are sufficiently high to prevent the operation of relays l, 2, and 3, respectively, and are provided to prevent the burning and arcing at contacts 2|, and 3| as well as to reduce radio interference.

Since the circuit to relay 2 is opened then relay 3 is the next retarded relay to operate. At armature 3| relay 3 opens the circuit of relay and also opens the circuit through the lower winding of differential relay 4 to cause its operation since the latter relay is now energized over its upper winding alone. At armature 42 and resting contact relay 4 opens the circuit to lamp L2 and at the working contact of armature 42 connects the circuit of lamp Ll to conductor 61 to illuminate the same. At armature 4| and resting contact relay 4 opens a further point in the circuit to the lower winding of relay 4 and at the working contact of armature 4| prepares the circuit to the lower winding of difierential relay 5.

Relay l deenergizes shortly after its circuit is opened at armature 3! and at armature reestablishes the circuit for relay 2. Relay 2 operates after an interval over its previously traced circuit and at armature 2| opens the circuit of relay 3 which accordingly deenergizes. At armature lil relay 3 again completes the circuit for relay 4 and also completes a circuit from conductor 67 by way of armature 4| and working contact through the lower winding of differential relay 5. Differential relay 5 now has both its windings energized with the result that said relay accordingly deenergizes. At armature 5| relay 5 closes its normally closed contacts before disconnecting armature 55 from its working contact thereby maintaining the circuit through the upper windings of differential relays 4 and 5 by way of armature 3|.

Relay l again operates over its circuit and at armature opens the circuit to relay 2 which deenergizes. At armature 2| relay 2 closes the circuit to relay 3 which accordingly operates I armature Ill.

after an interval.' At armature 3| relay 3 opens the circuit to relay I, and, since relay 4 alone is operated at this time, opens the circuits to both relays and with the result that relay 4 deenergizes. At armature 42 relay 4 opens the circuit to lamp LI and closes the circuit to lamp L2. At this time both differential relays 4 and 5 are in normal deenergized positions, relay 3 is operated and relay I therefore deenergizes to again start the sequential operation of relays I, 2, and 3.

The sequence of operation continues as follows:-Relay 3 operates and deenergizes relay I,

relay I deenergizes and operates relay 2, relay 7 2 operates and deenergizes relay 3, relay 3 deenergizes and operates relay i, relay I operates and deenergizes relay 2, and relay '2 deenergizes to reoperate 3 in a succeeding cycle as just described.

When relay 3 deenergizes the second time the initial circuit traced through point 68 is completed for both the upper and lower windings of relay 4 and only the upper winding of relay 5 with the result that relay 5 alone is operated as previously described. When relay 3 again energizes relay 4 is again operated as previously described, since the circuit through its lower winding is opened at armature 3I At armature 4?. relay 4 extinguishes lamp L2 and illuminates lamp LI. When relay 3 again deenergizes both windings of relay 5 are energized and differential relay 5 accordingly deenergizes. When relay 3 again energizes all the circuits through relays i and 5 are opened with the result that relay 4 deenergizes to extinguish lamp LI and illuminate lamp L2. Both differential relays 4 and 5 are in their normal deenergized positions and thereafter start on their next cycle of operations as just described when relay 3 deenergizes. From the foregoing it will be seen that for the first and each odd operation of relay 3 differential relay 4 is operated, that for the second and each even operation of relay 3 differential relay i is deenergized to flash the lamps LI and L2.

The flashing relay group continues to operate and flash the lamps LI and L2 until such time as the train passes over the crossing and operates contactor E2. In response to the operation of contactor E2 a circuit may be traced for energizing relays ERI and EH12 as follows: from positive pole of source B, contactor E2, and through the upper windings of relays ERI and ERZ in multiple to the negative pole of source B. At armature 6| relay ERI completes the previously traced stick circuit for relays ERI and EH2 to maintain these relays in their normally energized positions. At armature 62 relay ERI opens one point in the circuit to hell R which circuit is maintained at armature I8 of relay 6.

At armature E53 relay ERI disconnects one of the multiple positive pole of source B connections from conductor 67 but the relay group continues to function from the connection at At armature 6.4 relay EH2 opens a further point in the circuit to A. C. relay D and at armature Gt opens the circuit to extinguish arrow AI. At armature 65 relay ERZ completes a circuit for energizing A. C. relay U as follows: from the A. C. source, conductor it, armature 65, armature I5, gate up-centacts UC, A. C. relay U, to the A. C. source. At armature 'I'I relay U completes a circuit for operating the gate motor GM as follows: from the A. C. source, conductor 40, armature 11, through the gate motor GM to conduetor 39 and the A. C. source. In response to the operation of the gate motor GM the gates are raised to their normal position. Due to the raising of the gates contacts DC are closed to prepare a circuit for relay D, contacts UC are opened to open the circuit of relay U, and the gate limit switch GLS opens the circuit of relay 6. Relay U at armature 'I'I opens the circuit of the gate motor GM to stop the gates in their normal raised positions. Relay 6, upon deener gizing, at armature I8 opens the circuit of the bell R and at armature "I9 disconnects the positive pole of source 13 from conductor 61 to stop the operation of the flashing relay group and the flashing of lamps LI and L2.

West-bound trains on track 2 operate contactors WI and W2 to control relays WEI and WR2 in a manner identical with that described for east-bound trains on track I and it is therefore believed to be unnecessary to describe these circuits in detail. Armatures II, I2, I3, I4, I5, and I6 control similar or the same circuits as controlled by armatures GI, 62, 63, 6d, 65, and 66 need not be described in detail. A west-bound train operates contactor WI in approaching the crossing and opens the stick circuit of relays WRI and WR2 which deenergize. Relays WRi and WRZ close circuits for lowering the gates, for illuminating arrow A2 to indicate the direction of travel, for operating the bell R and for oper ating the flashing relay group to flash lamps LI and L2. After the train passes the crossing the operation of contactor W2 reenergizes relays WRI and WR2 to cause the gates to rise and the various signals to stop in a manner similar to that described for east-bound trains.

In case both an east-bound train and a westbound train should approach the crossing at about the same time then both the arrows AI and A2 are illuminated to indicate that a train is approaching the crossing on each track. In this case the first train to operate its contactor lowers the gates and starts the flashing relay group while the last train to pass the crossing and operate the corresponding contactor raises the gates and stops the flashing relay group.

Having described the invention, what is considered to be new and is desired to be protected by Letters Patent will be set forth in the following claims.

What is claimed is:

1. In combination, a conductor, two differential relays connected to said conductor, means for transmitting a plurality of pulses of current over said conductor to said relays, and means including circuits for operating only the first of said relays in response to the first and each subsequent odd pulse, for operating the second of said relays in response to the termination of said first and each subsequent odd pulse, for releasing said first relay in response to the second and each subsequent even pulse, and for releasing said second relay in response to the termination of said second and each subsequent even pulse.

2. In combination, a conductor, three relays and two differential relays normally connected to said conductor, means for connecting a source of current to said conductor, circuit arrange ments controlled by said three relays in response to said connection for repeatedly operating and releasing said three relays over said. conductor in a definite sequence after the initial operation of any one of said three relays regardless of which of the three relays is first operated, means whereby only one of said differential relays is Cal operated responsive to the connection of said source to said conductor, and means for operating the second of said differential relays in response to the first and each successive odd operation of a particular one of said three relays, for releasing said first differential relay in response to the first and each successive odd release of said particular relay, for releasing the second difierential relay in response to the second and each successive even operation of said particular relay, and for reoperating said first differential relay in response to the second and each successive even release of said particular relay.

3. In combination, a conductor, a first and a second plurality of relays normally connected to said conductor, means for connecting a source of current to said conductor, means including circuits controlled by said first plurality of relays for repeatedly operating and releasing successive relays in said first plurality of relays in a definite sequence cycle during the time said source is connected to said conductor, and means including circuits, said conductor and source for operating and releasing the relays in said second plurality once for every complete two cycles of operation of said first plurality of relays.

4. In combination, a conductor, three slow-tooperate relays normally connected to said conductor, means for connecting a source of current to said conductor, circuit arrangements controlled by said relays for operating said relays over said conductor in a definite sequence after the initial operation of any one of said relays regardless of which relay operates first, and a pair of relays alternately controlled by a particular one of said relays.

5. In combination, a group of relays comprising a first, a second, and a third relay, a conductor, contacts on the first relay normally connecting said conductor to the second relay, contacts on the second relay normally connecting said conductor to the third relay, contacts on the third relay normally connecting said conductor to the first relay, means for connecting a source of current to said conductor to simultaneously complete circuits for said relays through said contacts, said connections causing said relays to operate in a definite sequence after the initial operation of the first operated one of said relays regardless of which one of said relays operates first, and a pair of relays alternately controlled by a particular one of said relays.

6. In combination, a group of relays comprising a first, second, and third relays, a conductor, contacts on the first relay normally connecting said conductor to the second relay, contacts on the second relay normally connecting said conductor to the third relay, contacts on the third relay normally connecting said conductor to the first relay, means for connecting a source of current to said conductor to simultaneously complete circuits for said relays through said contacts, said connections causing said relays to operate in a definite sequence after the initial operation of the first operated one of said relays regardless of which one of said relays operates first, and differential relays operated in response to the operations of a particular one of said relays.

7. In combination, a group of relays comprising a first, second, and third relays, a conductor, contacts of the first relay normally connecting said conductor to the second relay, contacts on the second relay normally connecting said conductor to the third relay, contacts on the third relay normally connecting said conductor to the first relay, means for connecting a source of current to said conductor to simultaneously complete circuits for said relays through said contacts, said connections causing said relays to operate in a definite sequence after the initial operation of the first operated one of said relays regardless of which one of said relays operates first, and such a pair of relays alternately controlled over said conductor by a particular one of said relays.

MARTIN L. NELSON. 

